Hydraulic control apparatus



Patented June 29, 1954 UNITED STATES PATENT CFFICE 4 Claims.

This invention relates to improvements in devices for automatically controlling the volumetric eiiiciency of reciprocating positive displacement pumps in accordance with the discharge pressure and thence to a common destination. As it is generally well known, oil producing leases are normally dispersed over a wide area, and a common renery receives the crude oil produced from several, or all of the leases. Each lease, and frequently subdivisions thereof, is usually provided with a local battery of storage tanks to store the crude oil produced on the lease until it is needed at the refinery. Each battery of the local storage tanks is provided with one or more pumps, which discharge into a common header leading to the refinery. It is readily seen that if relatively close contact is not maintained between the operators on the leases, several of the pumps will frequently be operated simultaneously, resulting in an overloading of the common header. If the pressure in the common header becomes too great, a break will occur and there is possibility of losing a large quantity of the crude oil flowing therethrough.

The present invention contemplates a device which may be readily attached to the pumps located at the local tank batteries for automatically controlling the volume discharged from the pumps in accordance with the pressure in the main or common header, and to preclude developing excessive pressures in the header. The device is attached to either the suction or discharge valves of a reciprocating pump, and comprises a housing containing a hydraulically actuated piston assembly responsive to the header pressure. The piston is operatively associated with the stem of the valve to which it is attached and holds the valve in an open position when the header pressure exceeds a predetermined limit. The pump piston associated with the open valve will then merely idle, and the volume of liquid discharged from the pump will be automatically decreased. When the header pressure is decreased below the predetermined limit, the piston assembly of the present device will release the valve and allow the pump to resume normal operation.

An important object of this invention is to provide a novel device for automatically controlling the volumetric emciency of a reciprocating type pump in accordance with the discharge pressure thereof.

Another object of this invention is to provide a device which will vary the volumetric efficiency of a reciprocating type pump without appreciably affecting the mechanical efficiency thereof.

Another object of this invention is to provide a device for automatically controlling the volumetric elciency of a reciprocating type pump which may be conveniently attached to an existing pump without materially altering the existing pump.

A further object of this invention is to provide a device for controlling the volumetric efficiency of a reciprocating type pump which is controlled and operated by the pump discharge.

A still further object of this invention is to provide an eicient and inexpensive device for controlling the volumetric efficiency of a reciprocating type pump having a long service life.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which illustrate my invention.

In the drawings:

Figure l is a plan view of a reciprocating type pump, having a plurality of novel valve holding devices attached thereto.

Figure 2 is a partial side elevational view taken on line 2 2 of Figure 1.

Figure 3 is a sectional view taken on line 3--3 of Figure l.

Referring to the drawings in detail, reference character 2 designates a suitable duplex doubleacting pump adapted to be driven by any suitable power unit (not shown). The pump 2 is provided with the usual discharge conduit 4, and inlet conduit (not shown). rEhe discharge conduit 4 is connected by a conduit 6 to a surge chamber 8 in the usual manner. interconnected to the surge chamber 8, below the liquid level thereof, is a conduit li) extending transversely over the forward end l2 of the pump 2. The conduit I0 is provided with a pair of suitable relief valves I4 and l adjacent the suction valve housings I8 and 2li of the pump 2 for purposes as will be hereinafter set forth. A conduit 22 is connected to the conduit it between the surge chamber 8 and the relief valve lll, and extends transversely over the rear end 24 of the pump 2. A pair of suitable relief valves 2t and 28 is also provided in the conduit 22 adjacent the opposite suction valve housings 3u and 32 of the pump 2.

As clearly shown in Figure 3, the suction chambers 34 of the pump 2 are disposed below the pumping chambers 36 and are separated therefrom by a partition 38. At each end of each pumping chamber 36 an aperture 40 is provided in the partition 38 to provide communication between the suction chamber 34 and the pumping chamber 36. Each aperture 40 is alternately opened and closed by a suction valve 42 adapted to move up and down in its respective suction valve housing. The valve 42 contacts a valve seat 44 secured in the aperture 40 in its down position to seal off the suction chamber 34 from the pumping chamber 36. A plurality of radial ribs 46 is provided in the valve seat 44 and are connected to a cylindrical bushing 48 for receiving a rod 50 depending from the Valve 42. The bushing 48, through the medium of the rod 50, constrains the valve 42 to move in a true vertical direction, thereby assuring that the valve 42 will be correctly seated on the seat 44 when in a down position. A helical spring 52 is disposed above lthe valve 42 and in contact therewith constantly tending to retain the valve 42 on the seat 44. The upper end 54 of the spring 52 is anchored in a bore 56 provided in the suction valve housing cover 58. The cover 56 is secured to the suction valve housing by a plurality of bolts 60.

It is readily seen that when a suction is created in the pumping chamber 36, due to the movement of the pump piston (not shown) therein, the suction valve 42 will be raised off of the seat 44 and a portion of the liquid contained in the suction chamber 34 will be transferred into the pumping chamber 36. When the suction in the pumping chamber 36 is dissipated, by the complete lling thereof of the liquid previously contained in the suction chamber 34, the helical spring 52 will force the valve 42 down onto the seat 44.

A vertically arranged cylindrical housing 62 is disposed on the top of each suction valve housing cover 56. An aperture 64 is provided in each housing 62 in vertical spaced relation to the respective cover 58, communicating with the discharge conduit 66 of the Vadjacent relief valve (see Figures l and 2).

A piston member 68 is reciprocally disposed in the housing 62 and is provided with a plurality of sealing rings 'I0 secured in the outer periphery thereof in sealing relation with the inner walls of the housing 62. The upper end 12 of the plunger 68 is provided lwith an enlarged bore 'I4 for receiving one end of a helical spring 16. The opposite end of the spring T6 contacts a cover I8 threadedly secured to the upper end 80 of the housing 62. The spring 'I6 constantly tends to force the piston 68 downwardly into contact with a circumferential shoulder 82 provided in the housing 62 by a variation in the internal diameter thereof.

The lower end 84 of the plunger 68 is connected to a rod 86 extending downwardly through an aperture 88 provided in the cover 58 concentric with the bore 56. The rod 86 is sealed in the aperture 88 by a sealing ring 90 carried in the cover 58. The lower end 92 of the rod 86 is provided with a vertical bore 94 for receiving the valve stem 96 of the suction valve 42. A nut 98 is secured in the lower portion of the bore 94 loosely about the valve stem 96, and a nut |02 is secured to the upper end of the valvestem 96 above the nut 98 for purposes as. will .be hereinafter set forth. The rod..86 is also provided With CII a plurality of transverse apertures |04 in communication with the bore 94.

During normal operations of the pump 2, the piston 68 will be in the position shown in Figure 3, and the suction valve 42 will alternately move up and down as previously mentioned. The bore 94 is, of course, of sufficient length to permit free movement of the nut |02 therein during the normal operation of the pump .2.

The bore 94 communicates with a vertical bore |06 of smaller diameter having an apertured plug |08 secured in the lower end thereof. The bore |06 in turn communicates with another vertical -bore |-0 having a still smaller diameter. A valve seat 2 isprovided in the rod 86 at the intersection of the bores |06 and |0 for the reception of a 4ball valve |-|4. -The Valve ||4 is normally retained on the seat |2 by a helical spring I6 coacting with the plug |08 to preclude the flow of liquid from the bore |06 into the bore ||0 for purposes vas lwill -be hereinafter set forth.l A small ltransverse aperture ||8 is provided in the rod 86 adjacent the piston 68 in communication with the Ybore ||0. A small ltransverse 4aperture |20 is also providedy in the cover 58 `to provide limited communication between the pumping chamber 36 land the lower end of the housing 62 for purposes as will be hereinafter set forth.

Each cover "I8 is provided with an aperture |22 communicating with a gas ybleed line 24. A suitable valve |26 is i-nterposed in each of the bleed lines |24 (Figures l and 2), and all of the bleed lines are manifolded into a common header |28 leading to any desired disposal (not shown).

Operation Prior to placing the pump 2 in operation, the relief valves |4, |6, 26, and 28 are set at progressively higher vpressures .above the normal pressure of the discharge line 4. For example, the normal pressure of discharge line 4 vmay be 500 p. s. i. and the relief valve `I4 set at 510 p. s. i., relief valve I6 set at 520 p. s. i., relief valve 26 set Vat 530 p. s. i., and relief valve .28 set at 540 p. s. i.

Also prior to placing the pump 2 in operation, the bleedrvalrves |26 may be opened in order that any air orgas which may .be trapped in the housings 62 may be removed. After the pump 2 is placed in operation, a portion of the liquid contained in the pumping chambers 36 (Figure 3) will be forced upwardly through the respective small passageways |20 into the lower end of 'the housings 62 and the conduits l66. From the llower end of veach housing 62, the liquid will berforced further upward through aperture ||8 Vand bores ||0 and 14 to force the trappedair or gas through the respective bleed line |24 andmanifold |28. When liquid lbegins to flow from the bleedmanifold |28, indicating that-all of the air 01 gas has been removed, the valves |26 may be closed.

Also during `operation of the pump 2, .a portion of the liquid being pumped throughthe discharge line 4 will be forced through the conduit 6 into the surge chamber 8. From4 the surge chamber 8, a portion of the liquid will be forced into the conduits `lill. and-22 to the inlets of the relief valves I4, I6, 26 .and 28. Itisreadily seen, therefore, thatthe :pressure of the discharge line 4 will be constantly. transmitted-to the inlets of all of .therelief valves.

In the event the pressure in the discharge line 4increases above. the `normal pressure, as would occur if another-pump (not shown) started discharging into the line 4 or a valve (not shown) in the line 4 downstreamfrom the pump 12 were partially closed, the increased pressure would tend to open one or more of the relief valves.`

Assuming the pressure in the discharge line 4 has been increased sufficiently to operate the relief valve I4, a portion 'of the pumped liquid will be discharged through the relief valve I4 and discharge conduit 66 into the lower end of the housing 62 (Fig. 3) The resultant increased pressure below the lower annular face 84 of the piston 68 will force the piston upwardly in the housing 62. A portion of the liquid fromabove the piston 68 will be forced downwardly through bores 'I-4 and I I0 to open the valve I I4 and hence through bore IDB, plug 198, bore 94 and apertures |04 into the pumping chamber 36. The upwardly moving plunger 68 and rod 86 through the medium of the nuts 9S and IilZ and the valve stem 96, will lift the suction valve 42 off of the seat 44 to uncover the aperture 4E). It is then readily seen that as long` as the increased pressure is maintained on the lower face 84 of the piston 68, the suction valve 42 will be maintained in an open position. With the valve 42 in an open position, it is apparent that when the pump piston (not shown) in the pumping chamber 36 moves away from the valve 42, liquid from the suction chamber 34 will be transferred into the pumping chamber 36, and when the pump piston (not shown) moves toward the valve 42, the liquid in the p-umping chamber 325 will merely be forced back into the suction chamber 34 instead of into the discharge line `4. The volume of liquid being pumped by the pump 2 will therefore be decreased to reduce the pressure of the discharge line 4.

However, if the pressure of the discharge line 4 is further increased, the relief valves I6, 26, and 28 will in turn be opened to further decrease the volume of liquid pumped by the pump 2 until,

if necessary, the volume displaced by the pump 2 is reduced to Zero. It is then apparent that the pump 2 will merely idle.

When the pressure of the discharge line 4 decreases below the set pressure of the relief valves, the valves will be successively closed. As each relief valve closes, the pressure of the discharge line 4 will be precluded from its respective housing 82. The high pressure liquid retained under the plunger 68, after the closing of the respective relief valve, will gradually flow through aperture IIii and bores IIB and 14 to above the upper end 'I2 of the piston 63. The spring I6 will then force the piston 68 downwardly to the position shown in Figure 3 to release the suction Valve 42 for normal operation.

The relief valves may of course all be set at the same pressure, in which event an increase of pressure in the discharge line 4 above a predetermined limit would open all of the relief valves simultaneously to reduce the output of the pump 2 to zero. As soon as the pressure in the discharge line 4 drops below the predetermined limit, the pump 2 would automatically resume normal operation.

As previously stated, when one of the suction valves 42 is retained in an open position, liquid in the respective suction chamber' 34 will simply be transferred to and from the pumping chamber 36 by the action of the pump piston (not shown). The only forces then required to be overcome by the pump piston during movement toward one end of the pumping chamber are frictional forces and the force exerted upon the piston by the suction pressure, which is normally low as compared to the discharge pressure. It

isthereforereadily seen that the work done by therparticular pump piston is reduced virtually fifty per cent when the suction valve at one end of its respective pumping chamber is retained in an open position. Since the power necessary to operate the pump piston will be proportionally reduced, the fuel consumed by the power unit (not shown) will be proportionally reduced. The mechanical eiiiciency of the entire pumping unit will not, therefore, be materially changed, whereas the volumetric eiciency will be reduced by twenty-five per cent.

It will be appreciated that the present devices may be utilized with the discharge valves (not shown) of thepump 2, instead of the suction Valves 42, if desired. The housings -62 would then be disposed on the discharge valve housings I3IJ (Fig. l), and the devices would cooperate with the discharge valves (not shown) in a manner similar to that explained above for the suction valves 42 when the pressure in the dischargeline 4 exceeded a predetermined limit.

From the foregoing, it is apparent that the present invention provides a novel device which may be conveniently attached to an existing pump, and which will -automatically control the volume of liquid discharged from the pump without materially affecting the mechanical efficiency thereof. Also, the device will be operated by the pump discharge, thereby precluding the necessity of providing an extraneous source of power for its operation. Furthermore, when the devices are provided on all of a group of pumps discharging into a common header, the header pressure will not exceed a predetermined limit, notwithstanding the simultaneous operation of all the pumps.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification .and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

I claim: l

1. In combination with a reciprocating type pump having suction and discharge valves therein, a housing, a piston reciprocally disposed in said housing, lifting means carried by said piston for moving one of said valves to an inoperative lposition when said piston is moved in one direction, a relief valve communicating with the discharge of the pump downstream of the pump discharge valves, the discharge of said relief valve communicating with said housing beneath the piston so that when the pump discharge pressure exceeds a predetermined limit a portion of the pumped liquid enters said housing to move said piston in said one direction, and spring means to move said piston in the opposite direction for releasing said valve when the pump discharge pressure decreases below the predetermined limit.

2. A device for controlling the volumetric efficiency of a reciprocating type pump having suction and discharge valves therein, and comprising a housing, a piston reciprocably disposed in said housing, lifting means carried by the piston for lifting one of said valves to an open position when said piston is moved in one direction, relief valve means downstream of the pump discharge valves for introducing a lportion of the liquid discharged by the pump into one end -of said housing against one side of the piston so aces-,227:

that when the pump discharge pressurefexceeds a predetermined limit said piston is moved in' one direction, anexhaust passageway for theI opposite end of said housing to discharge liquid from said opposite end of said housingrwhen said pis-- ton is moved in said one direction, and .mea-nsto move said piston in the opposite direction to the first mentioned direction when the'pump dis charge pressure decreases below a' predetermined pressure to release said valve for normal operan tion.

3. A device for controlling the volumetric eiciency of a reciprocating type ypump having suction' and discharge valves therein, comprising a housing, a piston reciprocally disposed inV said housing, spring means for moving said piston in one direction, a rod carried by said piston, a .bore in said rod for receiving a portion of one of said valves whereby said valve will operate in a normal manner when said `piston is in one position, stop means in said bore cooperating with said one valve for moving said valve to an open position when said piston is moved in a direction opposite to said iirst mentioned direction, relief valve means in the discharge line of the pump for introducing a portion of the liquid discharged from the pump into one end of said housing against one side of the piston to move said piston in said opposite direction when the pump discharge pressure exceeds a predetermined limit, and means for transferring said portion of liquid introduced into said housing to the opposite end of said housing when the pump discharge pressure decreases below a predetermined pressure.

4; A devicefor controlling. the volumetric AeiliciencyfV of a reciprocatingtype pump'having suction and discharge valves therein, comprising a housing,` a piston reciprocally disposed in said housing, spring means for moving said piston in one'direction, lifting means carried by the piston for moving one of said valves to an inoperative position when said piston is moved in the opposite direction, said relief valve means in the pump discharge line downstream of the pump discharge valves for introducing a portion of the liquid pumpedV bythe pump into said housing beneath the piston for moving said piston in said opposite direction when the pump discharge pressure exceeds a predetermined limit whereby the volumetric elciency of the pump is automatically decreased, and mea-ns for releasing the pressure of the liquid introduced into said housing when the pump discharge pressure decreases below a predetermined pressure.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,008,816 Hamilton Nov. 14, 191'1 2,018,150 Rockwell Oct. 22, 1935 2,161,828 Lamberton June 13, 1939 2,317,119 Stevens Apr. 20, 1943 2,336,526 Bristol Dec. 14, 1943 2,433,220 Huber Dec. 23, 1947 FOREIGN PATENTS Number Country Date 265,275 Great Britain Feb. 22, 1927 

